knock on wood vs remark

knock on wood

verb
  • To take a customary action to ward off some misfortune that is believed to be attracted by a presumptuous statement. 

intj
  • Hopefully; a self-directive to undertake the customary action to ward off bad luck. 

remark

verb
  • To pay heed to; notice; to take notice of, to perceive. 

  • To express in words or writing; to state, as an observation. 

  • To make a remark or remarks on, to comment on (something). 

noun
  • make a remark 

  • A casual observation, comment, or statement 

  • An expression, in speech or writing, of something remarked or noticed; a mention of something 

  • An act of pointing out or noticing; notice or observation. 

How often have the words knock on wood and remark occurred in a corpus of books? (source: Google Ngram Viewer )